The high and low pressure outputs of the primary flow element of a differential pressure fluid flow meter are traditionally conveyed through conduits to a pressure transducer whose electrical output is communicated to a instrumentation center by a transmitter. It is necessary, however, to occasionally conduct maintenance on or calibrate the transmitter. For this purpose there is inserted between the pressure conduits and the pressure transducer a valve manifold that allows the respective high and low pressure conduits to be closed in order to isolate the pressure transducer from the process flow or the high and low pressures existing in the manifold can be equalized by a single valve in the manifold in order to calibrate the transmitter. In process applications where the fluids contain particulate matter maintenance must be performed to cleanse deposits of the particulate matter from the internal passageways and portions of the primary flow element in order to maintain the integrity of the flow measuring apparatus. The cleaning process requires significant disassembly of the manifold and transmitter combination resulting in untimely delays in getting the system back on line.
Thus, it is the primary object of the present invention to provide a valve manifold for a process flow meter assembly whose internal passages can be cleansed of particulate matter through a rodding process that does not require disconnection of the pressure transducer and transmitter from the valve manifold and utilizes a rod inserted in the manifold passages to break down or remove obstructions and adherent material.